SYNODONTIS. 



373 



inner, the former with long slender branches, which may bear secondary branches, the 

 latter with tubercular ramifications. Gill-opening not extending downwards beyond the 

 root of the pectoral fin. Occipito-nuchal shield rough like the occiput, obtusely tecti- 

 form, once and a half to once and two-thirds as long as broad, the posterior processes 

 pointed or truncate. Humeral process a little longer than broad, flat or with a very 

 indistinct keel, rugose, acutely pointed, extending as far back as the occipito-nuchal 

 process or not quite so far. Skin smooth, without villosities. Dorsal fin with I 7 rays ; 

 the spine strong, curved, feebly serrated behind, distinctly but finely serrated in 

 front, as long as or a little shorter than the head, the soft terminal part usually 

 produced into a short filament. Adipose dorsal fin three to four times as long as deep, 



Measurements (in millimetres). 



Total length (without caudal) 425 



Greatest depth 115 



Length of head 110 



Width of head 85 



Length of snout 54 



Diameter of eye 14 



Interorbital width .- 44 



Width of mouth 24 



Maxillary barbel 88 



Outer mandibular barbel 77 



Inner mandibular barbel 34 



Length of dorsal spine 115 



Basal length of dorsal fin 50 



,, „ adipose fin 155 



Greatest depth of adipose fin 40 



Length of pectoral spine 124 



400 



108 



108 



80 



56 



10 



40 



24 



132 



86 



39 



105 



53 



3. 



390 



110 



107 



78 



52 



13 



41 



25 



125 



76 



37 



107 



54 



138 



151 



32 



37 



107 



111 



4. 



5. 



6. 



7. 



8. 



9. 

 170 



10. 



123 



350 



325 



245 



220 



200 



94 



100 



62 



54 



47 



40 



33 



91 



95 



67 



64 



57 



48 



37 



67 



72 



50 



43 



38 



32 



27 



48 



48 



34 



33 



27- 



24 



18 



11 



J2 



11 



10 



9 



8 



7 



32 



37 



25 



22 



20 



16 



13 



22 



23 



18 



18 



13 



12 



10 



80 



63 



52 



59 



42 



51 



35 



62 



55 



38 



35 



30 



32 



25 



27 



27 



20 



19 



16 



17 



12 



86 



95 



60 



63 



49 



44 



30 



48 



45 



33 



30 



29 



24 



17 



127 



127 



90 



80 



79 



64 



45 



30 



33 



33 



20 



18 



17 



11 



86 



93 



62 



59 



48 



45 



31 



1, 10. Khartum. — Petherick. 



2, 4. Assuan. — Loat. 



3, 7. Ibrim. — Loat. 



5. Ahmed Aga. — Loat. 



6, 8. Samannud. — Loat. 

 9. Abu Hor. — Loat. 



